Arrangement for an operator&#39;s seat with a foot control

ABSTRACT

Arrangement for an operator&#39;s seat with a foot control for a working machine which can be operated by an operator, the operation of which occurs through the adjustment of the foot control (30) to different angular positions. The foot control acts as a support for at least one of the operator&#39;s feet during work and is connected to the seat unit (5) of the operator&#39;s seat in such a way that the foot control is connected to the seat unit and is so arranged as to accompany it as it moves. The movements of the seat unit and the accompanying foot control are determined by a guide arrangement connected to the operator&#39;s seat, which guide arrangement permits the movement of the operator&#39;s seat towards and away from the working machine between different positions for varying the distance between the operator and the working machine without affecting the position of the foot control relative to the seat unit through the aforementioned movements. The foot control is adjustable in relation to the seat unit, in this way giving the operator an ergonomically correct working position irrespective of his physical size. The seat unit (5) is supported by a telescopically extending upright (9) which can be displaced along the guide. The foot control is supported by a foot support unit (1) which can be moved between different heights along the upright (9). Arranged between the foot control and the upright is an essentially horizontal supporting plane (29) for the operator&#39;s feet. The upright is inclined rearwards in a direction away from the working machine and constitutes a sloping path for the foot support unit, such that a change in position in the vertical sense will also produce a pre-determined change in position in the horizontal sense.

TECHNICAL FIELD

The present invention relates to an arrangement for an operator's seatwith a foot control for a working machine which can be operated by anoperator, the operation of which occurs through the adjustment of thefoot control to different angular positions, in conjunction with whichthe foot control is so arranged as to act as a support for at least oneof the operator's feet during work and is connected to the seat unit ofthe operator's seat in such a way that the foot control is connected tothe seat unit and is so arranged as to accompany it as it moves, andthat the movements of the seat unit and the accompanying foot controlare determined by a guide arrangement connected to the operator's seat,which guide arrangement permits the movement of the operator's seattowards and away from the working machine between different positionsfor varying the distance between the operator and the working machinewithout affecting the position of the foot control relative to the seatunit through the aforementioned movements, in conjunction with which thefoot control is adjustable in relation to the seat unit, in this waygiving the operator an ergonomically correct working positionirrespective of his physical size, and in conjunction with which theseat unit is supported by a telescopically extending upright which canbe displaced along the guide.

TECHNICAL PROBLEM

There are within industry many work operations that are performed in aseated position and are associated with repeated and one-sided patternsof movement, such as precision operations in the areas of assembly, themachining of materials and certain manufacturing operations. Workoperations which involve the simultaneous actuation of controls andmachining of material call for well synchronized and coordinatedmovements of the arms/hands and legs/feet and good conditions of visionso as to avoid exposure to unnecessary physical stress. For work of thistype the work place itself (table, chair and equipment) must be sodesigned as to provide a good working position for every individual.

An example of work of this type is provided by machine sewing. Thisinvolves performing precision work at a high rate of working, whichcalls for well synchronized movements of the arms, hands, back, legs andfeet, at the same time as which the eyes must be directed towards thefoot and the needle of the sewing machine. Working under such conditionsplaces extremely high demands on the ergonomic design of the work place.No great stresses are imposed on the muscles and joints by sewingmachine work, although the stresses which are imposed are often of asustained nature. Muscles and joints in the back, the neck and theshoulders frequently have to adopt the same position for a long time.Many seamstresses in time experience permanent aching mainly in theshoulders, the neck and the back. There is a good deal of evidence tosuggest that this is due to the fact that the work place did not providea good working position. Most of the present-day work places for sewingmachinists do not satisfy the requirements in respect of a high degreeof adaptability to suit individuals. It is common to find that the chairis unsuitable, the table is at the incorrect height, or the controls arein the wrong position. This can give rise to fixed and static workingpositions.

The sewing machinist's traditional work place consists of a sewingmachine/motor, a table top/stand, controls and a chair. The machine,motor, table, stand and operating controls together form a unit. Thefree-standing chair is often a simple work chair. The layout of the workplace is essentially by the function of the sewing machine and to alesser extent by human requirements and anthropometric dimensions.Certain possibilities for adjustment are provided, although these aretime-consuming and difficult to perform. The range of variation is alsotoo small. What this results in in practice is that no adjustments oronly simple adjustments are made.

DESCRIPTION OF THE PRIOR ART

The present invention constitutes a direct further development of thearrangement in accordance with Swedish patent specification No.81037251, which relates to a work place with an operator's seat which iscapable of being displaced between different positions along a guidetowards and away from a working machine. The foot control of the workingmachine accompanies the seat as it moves. The foot control is adjustableto various positions in relation to the seat unit. The previouslydisclosed solution represents an early stage in the development work inwhich the fundamental problems associated with the working position weresolved.

The aim of the present invention is, as a result of further developmentwork, to further increase the possibility for varied working positionsand to facilitate leaving the operator's seat and to simplify itsadjustment.

SOLUTION

The aforementioned aim is achieved by an arrangement which ischaracterized in that the foot control is supported by a foot supportunit which can be moved between different heights along the upright, inthat there is arranged between the foot control and the upright anessentially horizontal supporting plane for the operator's feet, and inthat the upright is inclined rearwards in a direction away from theworking machine and constitutes a sloping path for the foot supportunit, such that a change in position in the vertical sense will alsoproduce a predetermined change in position in the horizontal sense.

The invention is described below in greater detail in relation to anillustrative embodiment with reference to the accompanying drawings, inwhich

FIG. 1 shows a perspective view of the arrangement in accordance withthe invention,

FIG. 2 shows a perspective view of a foot unit included in thearrangement,

FIG. 3 shows in entirely diagrammatic form a number of componentsincluded in the foot unit, and

FIG. 4 shows a side view of the arrangement included in a work placewith an operator at work.

The arrangement for an operator's seat in accordance with the inventioncomprises a foot support unit 1 with a foot control 2. The foot supportunit is connected to an operator's seat 3 which consists essentially ofa sub-frame 4 and a seat unit 5. The latter consists essentially of aseat cushion 6 and a back rest 7. The back rest 7 is supported in aconventional manner by a rail 8, which is adjustable to differentheights relative to the other part of the sub-frame and to differentangled positions (and thus different positions in the horizontal sensefor the back rest) relative to the subframe for the purpose of adjustingthe back rest relative to the seat cushion. The back rest 7 can eitherbe freely articulated relative to the rail 8, or can be adjustable toand lockable in various angled positions relative to the rail.

The sub-frame also has a telescopic upright 9 which supports the seatunit 5 and is connected at its base to a carriage 11 included in thesub-frame, by means of which the entire operator's seat can be displacedrelative to a base 12, i.e. usually a floor, and also relative to a worktable 13, part of which is shown in FIG. 4, and thus relative to aworking machine 14 supported by the work table 13. The working machine14 may consist of, for example, a sewing machine for professionalmachining, although other working machines may also be appropriate.

The telescopic upright 9 consists of two telescopic components 15, 16,one of which is in the form of a lower telescopic component 15 which issecurely attached to the carriage 11, and the other is in the form of anupper telescopic component 16 which can be displaced telescopicallyrelative to the lower part and which at its upper end supports the seatunit 5, more specifically a supporting frame 17 for the seat cushion 6.One telescopic component 15 extends inside the other telescopiccomponent 16, which is designed as a hollow section, preferably a boxsection of rectangular cross-section. The lower telescopic component 15is also executed with advantage as a box section of identical form tothe upper telescopic component, so that the latter can be moved with agood fit along the lower telescopic component and can be guided by itsinward-facing surfaces along the outward-facing surfaces of the lowertelescopic component. The upright 9 is thus adjustable with regard toits length for the purpose of displacing the seat unit 5 to variouspositions relative to the working machine 14. As will be appreciatedfrom the drawings, the upright 9 is inclined rearwards at a suitableangle relative to the base 12. The telescopic lengthening or shorteningof the upright 9 is appropriately achieved by means of a power source,for example a drive motor, which is not shown in the drawing, but whichmay, for example, be an electric motor with a rotating drive shaft and apower transmission arrangement so executed as to permit a linearfore-and-aft movement to be obtained. For example, the drive motor maybe installed on the telescopic component 16 and may cause to rotate viaa gear drive a screw, i.e. a threaded rod, so supported as to be capableof rotatable inside the telescopic component 16, onto which rod isscrewed a nut which is securely attached to the upper end of the lowertelescopic component 15. Alternatively, the power may be transmitted viaa rack, in which case the electric motor is securely attached to one ofthe telescopic components, for example the component 15, whilst the rackis securely attached and can be displaced together with the othertelescopic component 16. The electric motor may appropriately be a d.c.motor which can easily be reversed by changing over the poles.

The carriage 11, on which the operator's seat is able to move relativeto the base 12, exhibits two front and two rear wheels 19, 20. Theseessentially constitute supporting points for the carriage at its fourcorners. The two rear wheels are so supported as to be rotatable at therear end of two arms 21 and are intended to roll on the base 12. The twoarms 21 are secured at the front to the lower end of the upright 9, morespecifically the fixed, lower telescopic component 15, and diverge fromone another in the rearward sense in such a way that the two wheels 20are situated at a sufficient distance from one another for goodstability to be achieved. Similarly, the two front wheels 19 aresituated at a well dimensioned distance from one another to either sideof the upright 9 and with advantage ahead of its lower end and are sosupported as to be rotatable in a holder 22 which is rigidly attached tothe lower telescopic component 15 of the upright.

Also a part of the operator's seat is a guide arrangement 23, theposition of which is fixed relative to the work table 13 and thus to theworking machine 14. The guide arrangement is securely connected in theexample shown to a component 24 of a stand belonging to the table 13,which stand is not shown. The guide arrangement is so executed withadvantage that it can be placed in one of a large number ofpre-determined positions relative to the stand of the work table. Theguide arrangement 23 is divided in the example shown into two guides 25,26 which extend parallel to one another. These two guides 25, 26 consistof tubes which extend along the base 12 and are supported on the base attheir two ends in such a way that the tubes suitably extend at a certaindistance from the base. Arranged at the rear, free end of the guides aresupporting elements 55 which rest against the base 12. It is notnormally necessary for the supporting elements 55 to be secured to thebase, since the guides 25, 26 are anchored at their front end. These areconnected to one another at a predetermined mutual distance by means ofa connecting element 56 in the form of a flat metal plate or similarwhich can be screwed in a number of alternative positions to thesections 24 making up the stand. The tubes may, for example, exhibitcircular cross-section. A slide 27 in the form of a tubular sleeve canbe displaced along each of the two guides 25, 26, which sleeve enclosesthe guides and is securely attached to the carriage 11 below the holders22. Each of the two sleeves 27 exhibits a recess 28 directly oppositethe wheels 19, which extend through these recesses and are designed torun on the guides 25, 26. The wheels are with advantage designed withflanges or some other suitable form such that the wheels will achievegood contact against the tubes and will be provided with lateralguidance also by means of the sleeves 27.

By means of the guide arrangement 23 and the ability of the carriage 11to be displaced along it, the operator's seat is provided with theability to be displaced relative to the work table 13 and the workingmachine 14 along an ergonomically determined path, where the distance tothe working machine can easily be adjusted by the operator 18 himselftaking into account his physical size and his seated position. The routeof this path cannot be varied by the operator, however, but is specifiedat the time of installation of the work place and can thus be adjustedsubsequently by other personnel in order to provide correct adaptationto the position of the working machine 14.

The foot support unit 1 is supported by the upright 9 and for thisreason accompanies the operator's seat as it is displaced. The footsupport unit 1 exhibits a supporting plane 29 in the form of a plate forthe operator's feet situated in the immediate vicinity of the uprightand, in the example illustrated, in a horizontal attitude. Situated infront of the supporting plane 29 is a foot control 30 in the form of anactuator plate by means of which the working machine 14 is controlled bythe operator. The actuator plate 30 is continuously adjustable betweenpre-determined end positions relative to the supporting plane 29.Extending in a direction rearwards from the supporting plane 29 are longtubular or rod-shaped elements 31, 32 which constitute additional footrests for occasional support of the feet and for use when leaving theoperator's seat. The tubular or rod-shaped components 31, 32 form aframe-like structure in which the components 31, 32 are positioned insuch a way that the frame-like structure is situated above thesupporting plane 29. The components 32 extend to either side of theupright 9 essentially horizontally and transversely to the longitudinaldirection of the guide tubes 25, 26 and at an appropriate height aboveand at a certain distance horizontally from the rear edge 33 of thesupporting plane 29, in such a way that the components 32 are able toprovide a support for the operator's feet, so that the operator can sitwith his shoes to either side of the upright 9 with the heels resting onthe components 32 and with the toes resting against the supporting plane29. This position provides an occasional resting position to offer avariation in the working position during breaks, or with one foot on theactuator plate 30 and the other foot resting on one of the components32. The component 31 extends from the supporting plate 29 with aninclined part 34 angled obliquely upwards before then being transformedinto a hoop-shaped part which extends essentially horizontally with thesupporting plane 29 but on a higher plane relative to the latter. Thishoop-shaped part is essentially u-shaped with two legs 35 which areparallel to one another and run essentially parallel to the guide tubes25, 26 and to a slightly curved connecting piece 36 which connects thelegs together. The hoop-shaped part can form a support for the feet withthe operator seated or leaving the seat when the seat has been pivotedrelative to an imaginary vertical axis. The seat is, in fact, pivotallymounted on the upright 9, and more precisely at its upper part 9, insuch a way that the seat unit 5 can be pivoted through at least 90° toeither side in order to facilitate leaving the seat.

The supporting part of the foot support unit 1 consists of an extendedpart of the frame structure which supports both the supporting plane 29and the actuator plate 30. The supporting part is formed by an extensionof the component 34 with two parallel, horizontal parts 37 which supportthe supporting plane 29 together with cross-members (not shown) betweenthese tubular components. The tubular structure continues from thecomponents 37 as two components 38 extending forwards at a suitableangle relative to the supporting plane 29, which components constituteby means of two angle brackets 39, 40 a mounting for the actuator plate30.

The mounting for the actuator plate 30 is best appreciated from FIG. 3.Both angle brackets 38, 39 exhibit two parts which are parallel andvertical to one another with a mounting arrangement in the form of twostuds 43. These project into a curved slot 44 in two downward-angledparts 45 of the actuator plate 30. This mounting arrangement permits theactuator plate to be pivoted by the application of pressure to theactuator plate outside its geometrical axis of oscillation, that is tosay the pressure is applied by varying the angle of the foot. Attachedto the actuator plate 30 is a control device (not shown), which may beinstalled, for example, on the angle bracket 39 and which monitors theangular positions of the actuator plate via a control wire or sensor armand transmits any changes in position to the control element whichcontrols the working machine 14 in respect of certain of its functionsin a previously disclosed fashion.

The foot support unit 1 exhibits a guide sleeve 46 to which the footsupport unit 1 is securely attached via parts of the frame structure.The guide sleeve 46 in the shown example is in the form of a hollowsection of rectangular cross-section similar to the cross-sectional formof the upright 9 and having a dimension such that it fits closely overthe upper telescopic component 16, relative to which the guide sleeve isso arranged as to be displaceable. Through this displacement movementthe foot support unit can be adjusted to various heights relative to theseat unit 3 so as to suit different physical sizes of the operators. Thedisplacement movement is achieved by means of a power source 47 which isattached at its one end 48 to the telescopic part 9 of the upright andis attached at its other end 49 to the guide sleeve 46. This powersource is an arrangement which provides linear displacement movement ofthe guide sleeve 46 relative to the upper telescopic component 16 of theupright 9, and the foot support unit is fixed by means of the powersource in a specific position relative to the telescopic component 16and thus to the seat unit 3 and also accompanies the height adjustmentmovements of the seat unit relative to the lower telescopic component 15and thus to the work table 13 and the working machine 14. The powersource 47 consists, for example, of an electric motor which is soarranged as to cause to rotate a fixed nut threaded onto a rod 50, whichrod is caused by the rotation of the electric motor in one direction orthe other to be displaced longitudinally, either so as to shorten thepower source by raising the rod 50 in the direction of the attachment48, or so as to lengthen the power source, for which purpose the rod 50is lowered relative to the attachment 48. This type of powertransmission is self-locking, so that the power source will be lockedautomatically in the desired adjustment positions, which is alsoapplicable to the other power source for the displacement of thetelescopic components 15, 16 in the upright 9. It must also be mentionedthat the guide sleeve 46 is angled in the same way as the upright 9, sothat the supporting plane 29 accordingly extends essentially in thehorizontal plane at all times.

The operator is thus prevented by the operator's seat of the typeconcerned here from selecting the wrong working position to a certainextent because the seat cannot be displaced laterally relative to theworking machine 14, which reduces the risk of the operator sitting at anangle to the machine, for example. In the case of the sewing machine 14,for example, the guide arrangement 23 is installed in such a wayrelative to the stand of the working table 13 that the longitudinaldisplacement of the operator's seat in a straight line, i.e. the axis ofsymmetry of the guide arrangement 23, intersects the longitudinal axisof the sewing machine. This has been shown by ergonometric studies topermit an optimum working position for everyone. The considerable rangeof adjustment of the operator's seat in other respects enables it to beadapted to suit the operator's physical build.

When an operator's working osition is to be set, the operator positionshimself on the seat unit 5 facing towards the working machine, whereuponthe desired height of the seat unit relative to the work table 13 andthus to the working machine 14 is set by lengthening or shortening theupright 9. This is achieved by means of an operating control 51 on theseat unit which activates the power source (not shown) for the purposeof displacing the upper telescopic component 16 relative to the lowertelescopic component 15. The appropriate position of the foot supportunit 1 relative to the seat unit 5 can then be achieved, for example, byactivating a second operating control 52, in this case an electricalswitch for starting the power source 47. The foot support unit is raisedor lowered by means of the latter by causing its guide sleeve 46 to bedisplaced along the upright 9 in order to suit the length of theoperator's legs. The foot support unit 1 is imparted with an inclinedpath of movement by the inclined position of the upright, so that apre-determined change in position in the vertical sense will alsoproduce a predetermined change in position in the horizontal senserelative to the seat unit, which provides an accurately tested match tothe physical proportions of a normal person. A fairly short person withfairly short lower legs will thus require the foot control 30 to bepositioned not only closer to the seat unit in a vertical sense, butalso at a shorter distance in a horizontal sense from the seat unit inorder to the length of that person's upper legs. Finally, the horizontaldistance to the work table 13 and the working machine 14 can be set.This is most easily achieved by the operator displacing the operator'sseat 3 with the carriage 11 by taking hold of the work table 13 andpulling the seat towards the table or pushing the seat away from thetable. Alternatively, the operator may support himself on the base 12with one or both feet, in this way achieving the necessary displacement.Displacement is thus achieved by the carriage 11 running by its rearwheels 20 on the base 12 and by its two front wheels 19 on the guidetubes 25, 26. If sufficient friction is present between the carriage 11and the base, the operator's seat will remain in the set displacementposition, and otherwise a locking arrangement (not shown) is provided,for example for one of the rear wheels 20 or the front wheels 19, or bylocking the sleeve 27 relative to one of the guide tubes 25, 26. Theseat unit 5 should preferably be locked in some way against rotationrelative to the upright 9, either automatically through the presence ofa certain resistance to rotation in a sideways sense, or by means of amanually activated locking arrangement (not shown). The operator's seatis extremely stable, even when the seat unit 5 is being retained in itshighest position, due to the positioning of the supporting points andthe fact that the guides 25, 26 are enclosed by the sleeves 27. Althoughthese are not secured at one end, tipping is counteracted by therigidity of the guides and the sleeves 27.

The foot plate 30 can also be finely adjusted in respect of its angularposition in relation to the work of the working machine 14. This is doneso that the normal position of the actuator plate 30, that is to say theworking position which occurs most frequently, will provide the mostrestful angular position for the operator's foot 53 relative to thelower leg 54. This is set by means of the position-sensing mechanism(not shown), which transmits the angular movements of the foot plate 30to the control element. In the case of sewing machines it is the workingspeed of the machine which is regulated in such a way that pressureapplied to the front edge of the actuator plate will produce an increasein the speed, whilst sufficiently strong pressure in the oppositedirection will, in the case of at least certain machines, cause thedirection of operation to be reversed. The intermediate position, whichrepresents the neutral position, is adopted automatically when the footis removed from the actuator plate. The latter may suitably be coveredwith a layer of grooved rubber.

It is possible to leave the operator's seat by simply rotating the seatunit 5 relative to the upright 9 and, in the case of a high sittingposition, after lowering the seat unit 5 relative to the base andpossibly also pushing the seat unit rearwards on the carriage 11.Leaving the seat can be facilitated by placing the feet on the component35 of the tubular frame, which then has the function of a rung of aladder. The seat may also be pivoted through 180°, in which case thecomponent 36 of the tubular frame will adopt the corresponding function.

The invention is not restricted to the illustrative embodiment describedabove and shown in the drawings, but may be modified within the scope ofthe following patent claims. For example, the various adjustmentmovements can be performed entirely manually, in which case it isessential for the foot rest unit 1 to accompany the height adjustmentmovements of the seat unit and thus be fixed relative to the heightpositions of the seat unit, although the relationship can be varied. Thefoot plate can be replaced by a perforated, grating-like platform.

We claim:
 1. Arrangement for an operator's seat having a foot control for a working machine which can be operated by an operator, the operation of said machine occurring through the adjustment of the foot control to different angular positions, wherein there is provided a movable seat unit, said foot control is adapted to act as a support for at least one of the operator's feet during work and is connected to said seat unit so that the foot control accompanies said seat unit as it moves, a guide means operably connected to the seat unit for determining the movement of said seat unit and foot control, said guide means permitting the movement of said seat unit towards and away from the working machine between different positions for varying the distance between the operator and the working machine without affecting the position of the foot control relative to the seat unit during said movement, and said foot control being adjustable in relation to said seat unit so as to give the operator an ergonomically correct working position irrespective of his physical size, and wherein a telescopically extending upright supports said seat unit so that the seat unit is adjustable between different height positions relative to the working machine, said upright being displaceable along said guide means, a foot rest unit supports said foot control and is movable between different heights along said upright, and an essentially horizontal supporting plane is disposed between said foot control and said upright for the operator's feet, said upright being inclined rearwards in a sloping direction away from said working machine to constitute a sloping path for the seat unit and the foot rest unit so that a change in position in the vertical sense of th seat unit and the foot rest unit will also produce a predetermined change in position in the horizontal sense, and said foot rest unit being adapted to follow the seat unit in its adjustment movements and being also adjustable relative to the seat unit.
 2. Arrangement according to claim 1, wherein a tubular frame or the like extends at the sides of said upright and provides additional support for the operator's feet.
 3. Arrangement according to claim 2, wherein said tubular frame extends from said supporting plane to a higher level and has portions facing, on the one hand, transversely to the guide means and, on the other hand, essentially parallel to the guide means. 